Denon budget cartridge compared to $700 cartridge

At a minimum, you should hear better resolution and transients with the Blackbird, but a lot of that will depend on the rest of your analog "front end": turntable, tonearm, phono preamp, and preamp. So, to help other readers give you helpful advice, it would be good to know about the other analog components in your system.

Based on your system and your cartridge budget, I would recommend the Dynavector 17-D Karat or the Shelter 501 over the Blackbird. If you do that, you should also consider getting a new phono preamp. I am former owner of the Black Cube SE, and have real respect for it, but I don't think it is ideally suited for use with lower output MC cartridges.